Subject: Re: [PATCH v2 3/6] hook: introduce "git hook list"

From: Emily Shaffer <[email-masked]>
Date: Mon, 16 Aug 2021 17:36:22 -0700

On Thu, Aug 12, 2021 at 11:59:51AM -0700, Junio C Hamano wrote:
> 
> Emily Shaffer <[email-masked]> writes:
> 
> > +static int list(int argc, const char **argv, const char *prefix)
> > +{
> > +	struct list_head *head, *pos;
> > +	const char *hookname = NULL;
> > +	struct strbuf hookdir_annotation = STRBUF_INIT;
> > +
> > +	struct option list_options[] = {
> > +		OPT_END(),
> > +	};
> > +
> > +	argc = parse_options(argc, argv, prefix, list_options,
> > +			     builtin_hook_list_usage, 0);
> > +
> > +	if (argc < 1)
> > +		usage_msg_opt(_("You must specify a hook event name to list."),
> > +			      builtin_hook_list_usage, list_options);
> > +
> > +	hookname = argv[0];
> > +
> > +	head = hook_list(hookname);
> > +
> > +	if (list_empty(head)) {
> 
> The same "can't hook_list() signal an error by returning NULL?"
> comment applies here.
> 
> 	head = hook_list(hookname);
> 	if (!head)
> 		die(_("no such hook '%s'"), hookname);
> 
> or something?
> 
> > +		printf(_("no commands configured for hook '%s'\n"),
> > +		       hookname);
> > +		return 0;
> 
> If it is a normally expected state that there is no hook for the
> given name, signalling success by returning 0 here may be sensible,
> but then the message should at least go to the standard error stream
> to leave the standard output empty, so that a caller can reasonably
> do something like
> 
> 	for path in $(git hooks list "$1")
> 	do
> 		ls -l "$path"
> 	done
> 
> If we really want to show such a message, perhaps
> 
> 	if (list_empty(head)) {
>         	if (!quiet)
> 			warning(_("no commands configured"));
> 		return 0;
> 	}
> 
> The normal display just shows the path without saying "command %s
> will run for hook %s"; the warning probably should do the same.
> 
> Having said that, if it truly is a normal and expected state that no
> hook is defined for the given name, I actually think there should be
> no message.

Ah, I think you are saying "either return an error code and be chatty if you
want, or return an empty list and a success code, but pick one". Makes
sense to me.

No message + well-defined return code sounds fine. I'll do that.

> 
> > +	}
> > +
> > +	list_for_each(pos, head) {
> > +		struct hook *item = list_entry(pos, struct hook, list);
> > +		item = list_entry(pos, struct hook, list);
> > +		if (item)
> > +			printf("%s\n", item->hook_path);
> > +	}
> 
> > diff --git a/hook.c b/hook.c
> > index 37f682c6d8..2714b63473 100644
> > --- a/hook.c
> > +++ b/hook.c
> > @@ -96,22 +96,20 @@ int hook_exists(const char *name)
> >  struct list_head* hook_list(const char* hookname)
> >  {
> >  	struct list_head *hook_head = xmalloc(sizeof(struct list_head));
> > +	const char *hook_path = find_hook(hookname);
> > +
> >  
> >  	INIT_LIST_HEAD(hook_head);
> >  
> >  	if (!hookname)
> >  		return NULL;
> >  
> > -	if (have_git_dir()) {
> > -		const char *hook_path = find_hook(hookname);
> > -
> > -		/* Add the hook from the hookdir */
> > -		if (hook_path) {
> > -			struct hook *to_add = xmalloc(sizeof(*to_add));
> > -			to_add->hook_path = hook_path;
> > -			to_add->feed_pipe_cb_data = NULL;
> > -			list_add_tail(&to_add->list, hook_head);
> > -		}
> > +	/* Add the hook from the hookdir */
> > +	if (hook_path) {
> > +		struct hook *to_add = xmalloc(sizeof(*to_add));
> > +		to_add->hook_path = hook_path;
> > +		to_add->feed_pipe_cb_data = NULL;
> > +		list_add_tail(&to_add->list, hook_head);
> >  	}
> 
> I do not think this belongs to the step to add "list" command.  The
> log message does not explain or justify why have-git-dir goes away,
> either.

Ah, sure.

It seems like I also didn't update the documentation for 'git hook'
command during this commit. Will fix that as well.